Microscopic and sub-microscopic Plasmodium falciparum infection, but not inflammation caused by infection, is associated with low birth weight

Pregnancy-associated malaria is one of the leading causes of low birth weight in malaria endemic areas. In this study, 145 parturient women residing in areas endemic for Plasmodium falciparum in Lambaréné, Gabon, were recruited into the study after delivery, and the association of maternal P. falciparum infection, inflammatory response, and birth weight was studied. At delivery, 10% (15) of the mothers (12 were positive in both peripheral and placental blood smears, 1 was positive in peripheral blood only, and 2 were positive in placenta blood only) were positive for P. falciparum by microscopy and 23% (30) by real-time polymerase chain reaction (PCR). The level of C-reactive protein (CRP) was significantly elevated in microscopically P. falciparum-positive pregnant women (34 mg/L; 95% CI: 3-458) but not in those with sub-microscopic infections (6 mg/L; 95% CI: 1-40) compared with those free of P. falciparum infection (7 mg/L; 95% CI: 1-43). In a multivariate analysis, the presence of microscopic (adjusted OR = 28.6, 95% CI = 4.8-169.0) or sub-microscopic (adjusted OR = 13.2, 95% CI = 2.4-73.0) P. falciparum infection in pregnant women and age of mothers < 21 years (adjusted OR = 9.7 CI = 1.0-89.7), but not CRP levels, were independent predictors for low birth weight. This finding may have important operational implications and emphasizes the need for appropriate diagnostic methods in studies evaluating the outcome of pregnancy-associated malaria.     

Differential perpetuation of malaria species among Amazonian Yanomami Amerindians.

To determine whether malaria perpetuates within isolated Amerindian villages in the Venezuelan Amazon, we surveyed malaria infection and disease among 1,311 Yanomami in three communities during a 16-month period. Plasmodium vivax was generally present in each of these small, isolated villages; asymptomatic infection was frequent, and clinical disease was most evident among children less than five years of age (odds ratio [OR] = 6.3, 95% confidence interval [CI] = 1.4-29.2) and among persons experiencing parasitemias > or = 1,000 parasites/mm3 of blood (OR = 45.0, 95% CI = 5.5-370.7). Plasmodium falciparum, in contrast, was less prevalent, except during an abrupt outbreak in which 72 infections resulted in symptoms in all age groups and at all levels of parasitemia, and occasionally were life-threatening. The observed endemic pattern of P. vivax infection may derive from the capacity of this pathogen to relapse, while the epidemic pattern of P. falciparum infection may reflect occasional introductions of strains carried by immigrants or residents of distant villages and the subsequent disappearance of this non-relapsing pathogen.     

Effectiveness of chemoprophylaxis and other determinants of malaria in travellers to Kenya

Summary objective  To investigate the effectiveness of chemoprophylaxis and the determinants of malaria importation from Kenya.
method  In a population-based case-control study, 51 travellers from Bavaria diagnosed with falciparum malaria imported from Kenya (cases) and a sample of 383 healthy Bavarian travellers returning from Kenya (controls) were interviewed. Data were analysed by multiple logistic regression.
results  Mefloquine (OR = 0.055; 95% Cl 0.019-0.16) and chloroquine combined with proguanil (OR = 0.128; 95% CI 0.039-0.419) were highly protective against P. falciparum malaria, whereas other drugs were ineffective (OR = 1.225; 95% CI 0.536-2.803). Ineffective prophylaxis (10.4%) and non-prophylaxis (11.2%) were the main reasons for malaria importation. Travelling alone or with friends, male sex, and travel duration over 4 weeks could be identified as additional risk factors. The main reason for inadequate chemoprophylaxis was inappropriate medical advice (87.5%). Prophylaxis refusal occurred frequently despite correct advice (58.1%). Diagnosis was often delayed unnecessarily (27.5%).
conclusion  Malaria importation from Kenya could be reduced substantially (34%) by eliminating inappropriate medical advice.     

Association of ABO blood group and P. falciparum malaria related outcomes: a cross-sectional study in Ethiopia

Studies elucidate conflicting results about the relationships between ABO blood groups and Plasmodium infection outcomes in humans. This study examined association between ABO blood group and Plasmodium falciparum (P. falciparum) malaria related outcomes among 1065 malaria suspected febrile patients who attended Dore Baafano Health Center, southern Ethiopia, between December, 2010 and February, 2011. Blood specimens were collected and examined for malaria using Giemsa-staining, while stool specimens were examined for helminth infections using Kato-Katz method. Haemoglobin level and blood group were determined using hemocue machine and antisera hemagglutination test, respectively. Clinical data were also collected for the patients. Among the study participants, the proportion of O, A, B and AB blood groups were 40.1%, 30.1%, 29.0% and 14.3%, respectively, and P. falciparum malaria cases in the corresponding blood groups were 14.8%, 14.0%, 13.4% and 15.7%. The odds of non-severe P. falciparum malaria were not significantly different between individuals of blood group A versus O or B versus O or AB versus O. Mean haemoglobin concentration was significantly lower in P. falciparum infected blood type A individuals compared to P. falciparum infected blood type O (β=-1.25, 95% CI=-2.31 to -0.19) or non-A (β=-1.27, 95% CI=-2.23 to -0.32) individuals. The odds of P. falciparum malaria related anaemia was about three times higher in individuals with blood type A compared to those with blood type O (adjusted OR=2.82, 95% CI=1.05-7.56) or non-A individuals (adjusted OR=2.84, 95% CI=1.15-7.01). However, mean P. falciparum density did not significantly differ among patients according to their blood groups. In conclusion, individuals with blood group A had higher risk of anaemia compared to those with O and non-A phenotypes among P. falciparum malaria patients. However, there is a need to investigate the mechanism.     

Epidemiology of malaria in an area of low transmission in central India

A longitudinal study on malaria was carried out from 2003 to 2005 in an area of unstable malaria in the Panna district in central India. Both Plasmodium vivax and P. falciparum were prevalent; however, the risk of P. falciparum malaria was 31.6% (95% confidence interval [CI] = 29.6-33.6%), which is four times higher compared with that of P. vivax malaria (7.8%, 95% CI = 6.7-9%). An increasing trend was recorded in malaria prevalence from 30.2% in 2003 to 46.6% in 2004 (odds ratio [OR] = 2.0, 95% CI = 1.6-2.5) that increased to 58.6% in 2005 (OR = 1.6, 95% CI = 1.2-2.1). This increase was statistically significant (chi(2) = 120.5, degrees of freedom = 2, P < 0.0001). Anopheles culicifacies was the dominant vector of malaria and showed partial (< 50%) resistance to DDT, which indicated that DDT can still be used. Improved access to treatment facilities, combination therapy, and vector control appears to be the most promising method for controlling malaria in this region.     

Clinical features of children hospitalized with malaria--a study from Bikaner, northwest India

Severe Plasmodium vivax malaria in adults has been reported from Bikaner (northwestern India) but the reports on children are scanty. This prospective study was done on 303 admitted children of malaria. The diagnosis was done by peripheral blood smear and rapid diagnostic test. Further confirmation of severe P. vivax monoinfection was done by polymerase chain reaction (PCR). The proportion of P. falciparum, P. vivax, and mixed (P. falciparum and P. vivax) infection was 61.01%, 33.99%, and 4.95%, respectively. Severe disease was present in 49.5% (150/303) children with malaria, with the risk greatest among P. vivax monoinfection (63.1% [65/103]) compared with P. falciparum, either alone (42.7% [79/185]; odds ratio [OR] = 2.3 [95% confidence interval (CI) = 1.40-3.76], P = 0.001) or mixed infections (40% [6/15]; OR = 2.57 [95% CI = 0.88-7.48]). In children < 5 years of age, the proportion of severe malaria attributable to P. vivax rose to 67.4% (31/46) compared with 30.4% (14/46) of P. falciparum (OR = 4.7 [95% CI = 2.6-8.6], P < 0.0001) and 2.2% (1/46) of mixed infection (OR = 92 [95% CI = 24.6-339.9], P < 0.0001). The proportion of patients having severe manifestations, which included severe anemia, thrombocytopenia, cerebral malaria, acute respiratory distress syndrome, hepatic dysfunction, renal dysfunction, abnormal bleeding was significantly high in association with P. vivax monoinfection in 0-5 year age group, while the same was significantly high in association with P. falciparum monoinfection in 5-10 year age group. Similarly P. vivax monoinfection had greatest propensity to cause multiorgan dysfunction in 0-5 year age group (34.1% [17/41], P < 0.0001) in comparison to P. falciparum monoinfection, which had similar propensity in 5-10 year age group (36.8% [35/95], P = 0.039). Plasmodium vivax monoinfection was almost equally serious to cause significant mortality in comparison to P. falciparum (case fatality rate of severe P. vivax was 3.9% versus 3.2% of severe P. falciparum malaria; P = 1.0). This study reaffirms the evidence of severe P. vivax malaria in children in Bikaner.     

Risk factors for presentation to hospital with severe anaemia in Tanzanian children: a case-control study

In malaria endemic areas anaemia is a usually silent condition that nevertheless places a considerable burden on health services. Cases of severe anaemia often require hospitalization and blood transfusions. The objective of this study was to assess risk factors for admission with anaemia to facilitate the design of anaemia control programmes. We conducted a prospective case-control study of children aged 2-59 months admitted to a district hospital in southern Tanzania. There were 216 cases of severe anaemia [packed cell volume (PCV) < 25%] and 234 age-matched controls (PCV > or = 25%). Most cases [55.6% (n = 120)] were < 1 year of age. Anaemia was significantly associated with the educational level of parents, type of accommodation, health-seeking behaviour, the child's nutritional status and recent and current medical history. Of these, the single most important factor was Plasmodium falciparum parasitaemia [OR 4.3, 95% confidence interval (CI) 2.9-6.5, P < 0.001]. Multivariate analysis showed that increased recent health expenditure [OR 2.2 (95% CI 1.3-3.9), P = 0.005], malnutrition [OR 2.4 (95%CI 1.3-4.3), P < 0.001], living > 10 km from the hospital [OR 3.0 (95% CI 1.9-4.9), P < 0.001], a history of previous blood transfusion [OR 3.8 (95% CI 1.7-9.1), P < 0.001] and P. falciparum parasitaemia [OR 9.5 (95% CI 4.3-21.3), P < 0.001] were independently related to risk of being admitted with anaemia. These findings are considered in terms of the pathophysiological pathway leading to anaemia. The concentration of anaemia in infants and problems of access to health services and adequate case management underline the need for targeted preventive strategies for anaemia control.     

江苏省输入性疟疾初诊时间及影响因素分析

目的　了解江苏省输入性疟疾病例回国后就医行为特征,分析病例初诊时间影响因素,为输入性疟疾病例早期发现、防止重症病例发生及继发传播提供科学依据。方法　在中国疾病预防控制中心传染病报告信息管理系统和寄生虫病防治信息管理系统中,收集2019年江苏省报告的输入性疟疾病例个案信息以及发病及初诊时间信息。对输入性疟疾病例回国后就医行为及流行病学特征进行描述性分析,采用多因素logistic回归分析探索病例回国后初诊时间影响因素。结果　2019年江苏省累计报告输入性疟疾病例244例,病例初诊时间在1～12 d,平均初诊时间（1.53 ± 1.65） d、中位初诊时间1 d。出现首发症状当天就医的病例数最多（76例,31.1%）,68例（27.9%）第2天就医、46例（18.9%）第3天就医、54例（22.1%）3 d后就医,其中3例初诊时间在1周以上。归国时间在1月（14例,5.7%）和12月（13例,5.3%）、年龄在41～50岁（32例,13.1%）的外出务工人员中初诊时间延误者比例较高。多因素logistic回归分析发现,归国时间在3月[比值比（OR）= 0.16, P = 0.03, 95%可信区间（CI）：（0.03,0.85）]及有境外疟原虫感染史者[OR = 0.36, P = 0.001, 95% CI :（0.19, 0.67）]的病例初诊时间相对较短。结论　江苏省输入性疟疾患者主动就医及时性有待提高,有疟原虫感染史者就医更及时。     

河南省焦作市消除疟疾前后输入性疟疾疫情分析

河南省焦作市疾病预防控制中心（河南 焦作 454001）目的　分析河南省焦作市消除疟疾前后输入性疟疾流行病学特征,为开展消除疟疾后监测和防止输入性疟疾再传播提供科学依据。方法　通过传染病报告信息管理系统和寄生虫病防治信息管理系统收集焦作市消除疟疾前（2010—2016年）和消除后（2017—2021年11月）疟疾疫情数据及病例流行病学个案调查资料,进行描述性统计分析。结果　2010—2021年11月焦作市累计报告输入性疟疾病例74例。消除疟疾前后,输入性病例均以恶性疟为主,各虫种所占比例差异无统计学意义（[χ2] = 0.234,P > 0.05）,病例主要分布在武陟县、以20 ~ 59岁中青壮年男性为主,职业以境外务工的农民工、经商等为主,病例报告时间以每年6月和12月居多。消除疟疾前后,输入性疟疾病例均主要来自撒哈拉沙漠以南非洲国家,但消除疟疾后来自东南亚国家的比例有所上升,差异均有统计学意义（[χ2] = 5.989,P < 0.05）。消除疟疾后,患者从发病到确诊最长时长从27 d下降为18 d,中位时间从3 d缩短为2 d,3 d内确诊率由消除前的60.47%上升为消除后的83.87%（[χ2] = 4.724,P < 0.05）。医疗机构疟疾确诊及报告比例上升（[χ2] = 5.406,P < 0.05）。结论　2010—2021年焦作市输入性疟疾病例主要为恶性疟病例,消除疟疾后患者就诊意识和医务人员诊治能力有所提高;今后仍需加强完善疟疾监测响应体系,谨防境外输入疟疾再传播。     

The International Health Program: the fifteen-year experience with Yale University's Internal Medicine Residency Program

The factors affecting the development of patent Plasmodium falciparum gametocytemia were assessed in 5,682 patients entered prospectively into a series of antimalarial drug trials conducted in an area of low and seasonal transmission on the western border of Thailand. Of the 4,565 patients with admission thick smear assessments, 110 (2.4%) had gametocytemia. During the follow-up period 170 (3%) of all patients developed patent gametocytemia, which in 89% had developed by day 14 following treatment. In a multiple logistic regression model five factors were found to be independent risk factors at presentation for the development or persistence of gametocytemia during follow up; patent gametocytemia on admission (adjusted odds ratio [AOR] = 7.8, 95% confidence interval [CI] = 3.7-16, P < 0.001), anemia (hematocrit <30%) (AOR = 3.9, 95% CI = 2.3-6.5, P < 0.001), no coincident P. vivax malaria (AOR = 3.5, 95% CI = 1.04-11.5, P < 0.04), presentation with a recrudescent infection (AOR = 2.3, 95% CI = 1.3-4.1, P < 0.004), and a history of illness longer than two days (AOR = 3.3, 95% CI = 1.7-6.6, P < 0.001). Patients whose infections responded slowly to treatment or recrudesced subsequently were also more likely to carry gametocytes than those who responded rapidly or were cured (relative risks = 1.9, 95% CI = 1.3-2.7 and 2.8, 95% CI = 2.0-4.0, respectively; P < 0.001). These data provide further evidence of important epidemiologic interactions between P. falciparum and P. vivax, and drug resistance and transmission potential.     

Predictors of chloroquine treatment failure in children and adults with falciparum malaria in Kampala, Uganda

Chloroquine-resistant falciparum malaria is a serious problem in much of sub-Saharan Africa. However, it is desirable to continue to use chloroquine as first-line therapy for uncomplicated malaria where it remains clinically effective. To identify predictors of chloroquine treatment failure, a 14-day clinical study of chloroquine resistance in patients with uncomplicated falciparum malaria was performed in Kampala, Uganda. Among the 258 patients (88% follow-up), 47% were clinical failures (early or late treatment failure) and 70% had parasitological resistance (RI-RIII). Using multivariate analysis, an age less than five (odds ratio [OR] = 3.4, 95% CI = 1.8-6.3) and a presenting temperature over 38.0 degreesC (OR = 2.0, 95% CI = 1.1-3.7) were independent predictors of treatment failure. In addition, patients who last took chloroquine 3 to 14 days prior to study entry were significantly more likely to be treatment failures compared to patients with very recent (less than 3 days) or no recent chloroquine use. In areas with significant chloroquine resistance, easily identifiable predictors of chloroquine treatment failure might be used to stratify patients into those for whom chloroquine use is acceptable and those for whom alternative treatment should be used.     

Short report: therapeutic efficacy of chloroquine combined with primaquine against Plasmodium falciparum in northeastern Papua,Indonesia

Chloroquine combined with primaquine was evaluated for therapy of uncomplicated malaria caused by Plasmodium falciparum in nonimmune Javanese migrants to northeastern Papua, Indonesia. Subjects were randomized to treatment with standard chloroquine therapy (25 mg/kg in 3 doses over the course of 48 hours) with 30 mg primaquine administered daily for 28 days (n = 25) or a placebo of primaquine (n = 28). The 14-day cumulative incidence of therapeutic failure was 56% with primaquine and 79% with placebo (odds ratio [OR], 0.35; 95% confidence interval [CI], 0.1-1.3; P = 0.08). Primaquine administered daily created a marginally significant improvement in therapeutic efficacy at day 14, but not at day 7 (20% versus 36%; OR, 0.2; 95% CI, 0.1-1.8; P = 0.2) or day 28 (82% versus 93%; OR, 0.31; 95% Cl, 0.04-2.1; P = 0.23). This report corroborates studies suggesting that therapeutic doses of primaquine exert no discernible effect on parasitemia by P. falciparum.     

The incidence, risk factors, and outcome of transfusion-related acute lung injury in a cohort of cardiac surgery patients: a prospective nested case-control study

Transfusion-related acute lung injury (TRALI) is the leading cause of transfusion-related morbidity and mortality. Both antibodies and bioactive lipids that have accumulated during storage of blood have been implicated in TRALI pathogenesis. In a single-center, nested, case-control study, patients were prospectively observed for onset of TRALI according to the consensus definition. Of 668 patients, 16 patients (2.4%) developed TRALI. Patient-related risk factors for onset of TRALI were age and time on the cardiopulmonary bypass. Transfusion-related risk factors were total amount of blood products (odds ratio [OR] = 1.2; 95% confidence interval [CI], 1.03-1.44), number of red blood cells stored more than 14 days (OR = 1.6; 95% CI, 1.04-2.37), total amount of plasma (OR = 1.2; 95% CI, 1.03-1.44), presence of antibodies in donor plasma (OR = 8.8; 95% CI, 1.8-44), and total amount of transfused bioactive lipids (OR = 1.0; 95% CI, 1.00-1.07). When adjusted for patient risk factors, only the presence of antibodies in the associated blood products remained a risk factor for TRALI (OR = 14.2; 95% CI, 1.5-132). In-hospital mortality of TRALI was 13% compared with 0% and 3% in transfused and nontransfused patients, respectively (P < .05). In conclusion, the incidence of TRALI is high in cardiac surgery patients and associated with adverse outcome. Our results suggest that cardiac surgery patients may benefit from exclusion of blood products containing HLA/HNA antibodies.     

Association of FCgamma receptor IIA (CD32) polymorphism with malarial anemia and high-density parasitemia in infants and young children

Protective immunity against Plasmodium falciparum is partially mediated through binding of malaria-specific IgG antibodies to Fcgamma receptors. Polymorphic variability in Fcgamma RIIa (H/R-131) is associated with differential binding of IgG subtypes and malaria disease outcomes. However, the role of Fcgamma RIIa-131 variability in conditioning susceptibility to severe malarial anemia, the primary manifestation of severe malaria in holoendemic P. falciparum transmission areas, is largely undefined. Thus, Fcgamma RIIa-H131R polymorphism was investigated in 493 children who came to a hospital with acute malaria. Variation in Fcgamma RIIa-131 was not significantly associated with severe malarial anemia (hemoglobin [Hb] < 6.0 g/dL) or malaria anemia (Hb < 8.0 g/dL). However, relative to the heterozygous genotype, homozygotes for the R131 alleles were protected against high-density parasitemia (>or= 10,000 parasites/microL; odds ratio [OR] = 0.58, 95% confidence interval [CI] = 0.37-0.92, P = 0.02), while homozygotes for the H131 alleles were mildly protective (OR = 0.71, 95% CI = 0.45-1.13, P = 0.14). Additional multivariate analyses showed that infection with human immunodeficiency virus type 1 did not influence the associations between FcgammaRIIa-H131R polymorphism and malaria disease outcomes. Genotypic results presented here parallel data illustrating that parasite density is unrelated to the severity of anemia in children with acute malaria. Thus, although homozygosity for the R131 allele protects against high-density parasitemia, FcgammaRIIa-131 polymorphism does not protect against malaria anemia.     

2011-2017年福建省输入性疟疾流行态势及防控策略

目的 分析福建省2011-2017年输入性疟疾流行特征,为福建省顺利实现消除疟疾提供科学依据。方法 收集2011-2017年福建省输入性疟疾流行病学调查资料,运用SPSS 18.0软件对输入性疟疾的虫种、输入来源以及三间分布进行统计分析;对输入性疟疾首诊确诊的影响因素进行多因素logistic回归分析。结果 2011-2017年福建省共报告输入性疟疾病例632例,以恶性疟为主,占总病例数的67.6%(427/632)。输入来源地主要为非洲,占总比例数的85.1%(533/632);病例主要分布在福州,占总病例数的50.6%(320/632),其余地区散在分布。发病时间无明显季节性,全年均有输入性病例报告;发病人群多为青壮年,约占总病例的85.1%(533/632),男女性别比例为9.2:1(570/62)。从发病到确诊的时间大多在10 d以内,占总病例数的82.9%(524/632);首诊确诊455例,约占总比例的72%.首诊确诊的影响因素中,患者就诊前服用抗疟药物与首诊确诊率呈负相关[OR=0.175,95%CI(0.061~0.509)], 就诊前告知去过疟区[OR=132.964,95%CI(41.601~424.973)]及首诊机构为县级以上医疗机构[OR=27.951,95%CI(13.285~58.806)]这两个因素与首诊确诊率呈正相关;就诊前是否患过疟疾对首诊确诊率无影响(OR=1.496,95%CI(0.735~3.044))结论为适应我省目前的疟疾流行态势,制定了相应的防控策略:做好传染源的管理和控制,加强外出务工人员的疟疾防治知识健康教育,提高基层首诊医生对疟区回国人员的疟疾诊断意识,做到早发现、早诊断、早治疗。最大限度降低继发性传播风险,确保我省消除疟疾目标的顺利实现。     

Prognostic value of thrombocytopenia in African children with falciparum malaria

Thrombocytopenia is a common finding in malaria, but its prognostic value has not been addressed in children. The relationship between thrombocytopenia (platelet count < 100,000/mm3 on admission) and severity and outcome was investigated prospectively in children hospitalized with falciparum malaria in Dakar, Senegal, an area that is hypoendemic for malaria. Of 288 falciparum cases, 215 matched the 2000 World Health Organization definition of severe malaria. Median platelet counts were lower (98,000/mm3 versus 139,000/mm3; P < 0.02) among severe cases than in mild cases, and in children who died than among those who recovered (68,500/mm3 versus 109,000/mm3; P < 0.002). In severe cases, children presenting with a platelet count < 100,000/mm3 were more likely to die (odds ratio [OR] = 6.31, 95% confidence interval [CI] = 2.0-26.0). Moreover, multivariate analysis identified thrombocytopenia as an independent predictor of death (OR = 13.3, 95% CI = 3.2-55.1). Our data show an association between thrombocytopenia and either severity or prognosis in childhood falciparum malaria.     

Predictors of the failure of treatment with chloroquine in children with acute, uncomplicated, Plasmodium falciparum malaria, in an area with high and increasing incidences of chloroquine resistance

Resistance to chloroquine (CQ) in Plasmodium falciparum has reached unacceptably high levels in many endemic countries. The pre-treatment factors that identify the children who are at risk of treatment failure after being given CQ were evaluated in 385 children with acute, uncomplicated, Plasmodium falciparum malaria. These children each took part in one of six antimalarial drug trials conducted, between July 1996 and July 2004, in a hyper-endemic area of south-western Nigeria. Following treatment with CQ, 149 (39%) of the children failed treatment by day 7 or 14. In a multivariate analysis, an age of < or =7 years [giving an adjusted odds ratio (AOR) of 2.17, with a 95% confidence interval (CI) of 1.19-3.85; P = 0.01], an asexual parasitaemia of > or =100,000/microl (AOR = 2.17; CI = 1.08-4.35; P = 0.03), the presence of gametocytaemia (AOR = 2.08; CI = 1.14-3.85; P = 0.02) and enrolment >4 years after commencement of the study (i.e. after 2000; AOR = 2.13; CI = 1.3-4.0; P = 0.003) were found to be independent predictors at presentation of the subsequent failure of treatment with CQ. Compared with the other children, those who failed to clear their parasitaemias within 3 days and those who still had fever 1-2 days after commencing treatment were more likely to be treatment failures. Together, these findings may have implications for malaria-control efforts in all areas of sub-Saharan Africa where treatment of malaria depends almost entirely on antimalarial monotherapy.     

Predictive factors of malaria in travelers to areas where malaria is endemic

BACKGROUND: The differentiation of malaria from other causes of fever is difficult. The development of tools for rapid and specific clinical diagnosis is of paramount importance for the identification of individuals infected with malaria. METHOD: A 4-year prospective study to identify the clinical and biological variables associated with malaria included all patients suspected of having malaria who presented in the emergency department (ED) of a French hospital. RESULTS: Of 783 patients admitted to the ED with suspected malaria, 145 had positive findings of a thick smear for Plasmodium species, mainly Plasmodium falciparum (90.3%). In univariate analysis, the following 12 variables were significantly associated with diagnosis of malaria: older than 30 years, male sex, immigration to France from an area where malaria is endemic, a visit to sub-Saharan Africa, insufficient antimalaria prophylaxis, fever, chills, absence of diarrhea, a leukocyte count within the reference range, thrombocytopenia, and increased lactate dehydrogenase and bilirubin levels. In multivariate analysis, the factors predictive of malaria included a visit to sub-Saharan Africa (odds ratio [OR], 7.7; 95% confidence interval [CI], 2.8-21.3), a temperature of at least 38.5 degrees C (OR, 6.2; 95% CI, 2.8-13.3), chills (OR, 3.0; 95% CI, 1.4-6.6), thrombocytopenia (OR, 16.5; 95% CI, 7.1-38.3), and abnormally high total bilirubin levels (OR, 21.5; 95% CI, 6.4-72.5). However, alone or combined, these features had insufficient sensitivity (95.0%) and low specificity (55.0%) for the diagnosis of malaria. CONCLUSIONS: Malaria should be suspected in all patients presenting with complaints after travel to an area where malaria is endemic, and these patients should undergo blood microscopy.     

Predictors of the failure of treatment with pyrimethamine-sulfadoxine in children with uncomplicated falciparum malaria

The prevalence of pyrimethamine-sulfadoxine (PS)-resistant Plasmodium falciparum malaria has been increasing in sub-Saharan Africa or other parts of the world in the last one or two decades. The factors that identify children at risk of treatment failure after being given PS were evaluated in 291 children with acute, symptomatic, uncomplicated, P. falciparum malaria. The children took part in four antimalarial drug trials between July 1996 and July 2004 in a hyperendemic area of southwestern Nigeria. Following treatment, 64 (22%) of 291 children failed treatment by day 7 or 14. In a multivariate analysis, an age < or = 1.5 years (AOR=2.9, 95% CI 1.3-6.4, P = 0.009) and presence of fever (AOR = 3.3, 95% CI 1.28-7.14, P = 0.01) were independent predictors of the failure of treatment with PS at presentation. Following treatment, delay in parasite clearance >3 days (AOR = 2.56, CI 1.19-5.56, P = 0.016) was an independent predictor of the failure of treatment with PS. In addition, compared with the children who had no fever then, children with fever three or more days after starting treatment were more likely to be treatment failures. These findings may have implications for malaria control efforts in some sub-Saharan African countries where treatment of malaria disease depends almost entirely on PS monotherapy, and for programmes employing PS or PS-based combination therapy.     

Insecticide-treated bednets for the prevention of Plasmodium falciparum malaria in Cambodia: a cluster-randomized trial

OBJECTIVES: To validate and quantify the impact of insecticide-treated bednets (ITN) on malaria morbidity and mortality in Cambodia. METHODS: A paired, cluster-randomized trial of ITN was conducted in Rattanakiri, North East Cambodia. Thirty-four villages with a total population of 10,726 were randomized to receive deltamethrin-impregnated bednets or to control (no net provision). Cross-sectional surveys measured Plasmodium falciparum prevalence at baseline and 10 months after ITN distribution. Village malaria volunteers in control and intervention villages treated dipstick-positive P. falciparum cases with artesunate and mefloquine. The resulting passive surveillance data were used as an estimate of the incidence of clinical P. falciparum infections. RESULTS: There was a protective efficacy of 28% in P. falciparum incidence (adjusted rate ratio 0.72, 95% CI 0.47-1.08) and 9% in P. falciparum prevalence (adjusted prevalence ratio 0.91, 95% CI 0.65-1.28) in ITN relative to control villages; however, neither of these estimates reached statistical significance. Individual-level analysis indicated a greater reduction in P. falciparum prevalence among under 5-year-olds (adjusted OR = 0.63, 95% CI 0.26-1.53) compared to older individuals (interaction P = 0.042). The protective efficacy of 35% (95% CI -28, 67%) with respect to clinical P. falciparum incidence in under 5-year-olds was more pronounced than the corresponding estimates for prevalence but was again not significant. CONCLUSIONS: Lack of statistical significance in the results is likely to be due to a lack of power. The analysis provides further evidence for ITN effectiveness in South East Asia, particularly among individuals under 5 years of age.